Motion converting mechanism



' Aug. 21, 1951 E. A. REHWALD MOTION CONVERTING MECHANISM Filed Sept.13, 1949 INVENTOR. Edmund A Rehwa/d ATTORNEYS Patented Aug. 21, 1951MOTION CONVERTING' MECHANISM Edmund A. Rehwald, Rockford, Ill.,assignor' tor ianhen qolman-Gompany, Rockford, 111., a cor-1 n m o fofil i n s 7 Application September 13, I949, SerialNo. 115,399

4; Glaims.

This invention relates generally-to motion. con-.

ing doors or other reciprocating parts and: more particularly to amechanism in which the rotary ing sleeves 12 which are slidable alongspaced parallel guide rods [-3. Through themediunr of a link I4 or othersuitable connection, the motion motion of a unidirectional motor isconverted to of the car may be transmitted to a door or otherreciprocating motion of a guided: part through part to be operated. themedium of connecting memberof stud pro The chain l lies ina planeparalleling the path ject-ingrigidly from a flexible drive element suchof reciprocation of the carand is disposed adjaas an endless chain andengageablewith and cent the car on the side of the latteroppositemovable along oppositely facing surfaces on the 1 0 the actuating link.Opposite end portions of" the guided part which is disposed adjacentthechain chain loop mesh with and extend around and and linked to thedoor or other member to be are supported by sprockets l rotatablymounted actuated. on a suitable framework (not shown). One of Theprimary object of the invention is to prothe sprockets is driven bytheunidirectional vide a. motion converting mechanism of theabove 1 5 motorduring the operation of which the straight type having a driving memberwhich may be parallel runs of the chain move in opposite axrec-= tiltedrelative to the oppositely facing surfaces tions along parallel pathsandeachlink of the on. the guided part and still movefreely along chain,in passing from one path to the other, the latter without binding.traverses an intervening arcuate or semi-circular Another object is toeffect freedom of movepath which is defined by the sprocket I 5. mentbetween the connecting member orstud The chain is connected to the carl'l through and the oppositely facing surfaces by means of the medium ofa drive member Hiwhich projects a plurality of rotary elements iournaledon the from the chain toward the car for engagement member andrespectively engageable with the with one surface I? thereon againstwhich-the different surfaces when the member becomes member bears topush the car in one direction tilted, while traversing one of itsstraight paths and A more detailed object is to transmit motion a secondoppositely facing surface t,8 against from the chain to the guided partor car by which the member bears in pushing the car in meansof'a studhaving two axially spaced rollers the opposite direction whiletraversing the other iournaled thereon for engagement respectivelystraight path. The surfaces It! and it are diswith the opposed Walls ofa cross-slot on the posed in planes perpendicular to the path of car.reciprocation of the car H and, to permit the other objects andadvantages ofthe invention drive member to move around the sprocket inwill become. appa n m t foll wing passing from one run of the chain tothe other; tailed description taken in connection with the the surfacesare elongated in a direction transaccompanyin drawings, in which;versely of the car. When, as shown herein, the Fi ura is a pe spectiveview Qf. IZQ Q T t n rdrive member comprises a single promotion, the minmechanism embodying 21 DIQ Q UZ surfaces 17 and I8 face towardeachoth'er and v ntion. constitute the walls of a cross-slot in whichthe Fig. 2 is, a. fragmentary sectional. view hlifin drive member fitsquite closely in order to mini in he plane of the line 2. O Fig. mizethe backlash or looseness in the connection E 3 is. a fra men r ide. efiila-fiipnl Qf h between the chain and the car. Operation. of motiontransmitting t s w ng a. tilted 12051 the door or other part with ajerky motion is of the parts. thus avoided. While the drive member [iimay The invent on is espe ally adapted '0 5B in in some instances bejournaled on the chain, it a.v mechanism for converting the rotarymotion ispreferably made rig-id with the latter andein ofaunidirectional l c m r (not. shown)- the present instance includes astud I9 abutting 1.13 a c p to y mo ion suitable for Qperatr at one endagainst the side of one of the links ins s r m m r s h s ara e doorsor.the of the chain to and secured rigidlyto the latter like by means of aflexible drive element, such by pins as which are pressed. intotheend-of the as an endless chaintiihavinga driving connecstud and maybe used advantageously as the tion with a carriage or car H guided formove-.- pivots for joining the stud ink-to, the overlapping ment backand forth along a rectilineali' path-and ends of the adjacent links. Thepins; are held in connected: to a, garage door orother part, to. be pl eby a snap link 2! fitting over; the-other Teciprocated; Asshown-,.thecar comprises algen: 5'5 ends; ofrthe pins. l

While the chain link which supports the drive member l6 does mesh withthe teeth of the sprocket IS in passing around the arcuate portion ofits path, it is not guided accurately. Therefore, owing to theflexibility of the chain, the stud [9 tends to tilt laterally under thebending stresses to which it is subjected due to offsetting of the car II from the plane of the chain l0. Under these conditions one part of thestud engages one edge of one of the walls of the slot and another partof the stud axially spaced from the first part engages the opposite edgeof the other wall of the slot.

The present invention aims to avoid any danger of bending or locking ofthe stud in the crossslot under such conditions and to insure freemovement of the stud along the slot walls. This is accomplished throughthe provision of two independently rotatable elements 22 and 23 mountedon the stud in such manner that when the stud is tilted from its axisone element engages one wall of the slot and the other element engagesthe other wall so as to provide rolling contact at both points ofengagement between the stud and the car.

In the present instance, the rotary elements 22 and 23 are rollers which.are slightly smaller in diameter than the width of the slot and whichare journaled in end to end relation onto a cylindrical bearing surface24 intermediate the ends of the stud. Preferably, suitable bushings 25are interposed between the rollers and the bearing surface 24 to reducewear on the rollers. A shoulder 26 formed in the upper portion of thestud defines the upper end of the bearing surface and limits movement ofone roller 22 upwardly with respect to the stud while movement of theother roller 23 downwardly is limited by engagement of the roller with awasher 21 which is held in place against the lower end of the bearingsurface by a nut 28 threaded onto the projecting end of the stud. Ifdesired, a washer 29 may be interposed between the adjacent ends of therollers to keep the latter out of rubbing engagement with each other.

Means is provided on the rollers and on the car which coact to limitaxial shifting of the rollers relative to the slot walls so as to avoidany possibility of the rollers being forced out of the slot in the eventof excessive wearing of the rollers or the walls in service use. One ofthese means is in the form of a flange 29 which in this instance is onthe roller 22 and coacts with surfaces on the top of the car adjacentthe edges of the slot and the other means is a flange 30 on the otherroller 23 coacting with surfaces on the bottom of the car adjacent theslot.

With the chain moving along its path in a clockwise direction and thestud-moving with the chain along one of the parallel paths as viewed inFig. l, the rollers 22 and 23 engage the wall I"! to move the car I Ialong the rods I3 toward the sprocket I5. Due to the flexibility of thechain and the resistance of the car to movement along the guide rods,the stud is subjected to bending stresses and is tilted slightly out ofparallelism with respect to the walls. In the continued movement of thechain from the position shown in Fig. I, the stud moves around thesprocket and longitudinally of the slot with one roller engaging androlling along each of the respective slot walls (see Fig. 3). Thus, theupper roller 22 engages and rolls along the upper edge of the wall 11and the roller 23 engages and rolls along the lower edge of the otherwall 18, the degree of tilt being slightly exaggerated for purposes ofillustration.

4 With the stud moving along the walls in a direction away from theobserver as viewed in Fig. 3, the rollers rotate about the axis of thestud in the opposite directions indicated by the arrows. As the studmoves from the curved path around the sprocket into the other parallelpath of the chain, its movement longitudinally of the slot stops and therollers both act against the wall l8 to urge the car along the rods in adirection away from the sprocket.

The motion converting mechanism above described enables the stud to movefreely along the slot so as to eliminate binding between the two evenduring tilting of the stud out of parallelism with respect to the slotwalls. This desirable action is made possible by the use of the twoindependently rotatable rollers which are adapted to engage therespective slot walls and are free to rotate in opposite directions onthe stud thereby providing rolling contact and a con sequent reductionof friction between the stud and the slot walls.

I claim as my invention:

1. The combination of an elongated flexible power driven member movablesuccessively along spaced parallel paths through a semi-circularconnecting path, a car guided for movement back and forth along arectilinear path parallel to and spaced from the plane of said parallelpaths, said car having a cross-slot with opposed parallel wallsextending transversely of said paths, a stud secured to said member andprojecting laterally of the member and the slot and in between saidopposed walls, and two axially spaced rollers journaled on said stud andadapted to engage opposite edge portions of said walls, said stud andsaid rollers being movable along said slot as the stud moves around saidsemi-circular path with one of the rollers engaging an edge portion ofone of said walls and the other roller engaging the opposite edgeportion of the other wall when the stud is tilted out of parallelismwith respect to the walls.

2. The combination of an elongated flexible power driven member movablesuccessively along spaced parallel paths through a semi-circularconnecting path, a car guided for movement along said parallel paths andhaving thereon spaced parallel guide walls lying in planes perpendicularto said parallel paths, a stud disposed adjacent said walls andprojecting rigidly from said member, and two rollers journaled on saidstud in end to end relation and respectively engageable with oppositeedge portions of the different guide walls when the stud is canted outof parallelism with respect to the walls.

3. The combination of an elongated flexible drive element movable alonga path including an arcuate portion, a car guided for movement along apath spaced from said drive element, said car having a cross-slot withopposed walls extending transversely of the car motion, a stud securedto and projecting from said element into the space between said walls,said stud being movable in a direction longitudinally of said slot asthe stud is moving around said arcuate portion of said path with saidelement, and two axially spaced rotary elements on said stud positionedto engage opposite edge portions of said opposed walls with one of saidrotary elements adapted to roll along one of said walls and the otherrotary element adapted to roll along the other wall upon tilting theaxis of said stud during the movement of the stud along the slot.

4. The combination of an elongated flexible power driven element movablealong a pathly- REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 34,400 Barden Feb. 18, 1826399,593 Worth Mar. 12, 1889 1,097,333 Kinmont May 19, 1914 10 1,128,545Swanson Feb. 16, 1915 1,641,067 Connelly Aug. 30, 1927

